Radio shielding sealing gasket



Aug. 22, 1950 A. A. PIERSON, JR

RADIO SHIELDING SEALING GASKET Filed March 22, 1945 Patented Aug. 22,1950 UNITED STATES PATENT OFFICE I 2,519,85c v RADIO :SHIEIDING SEALINGVGASKET Adrian A. Pierson, Jr., Utica, N. Y.

Application March 22, 1945, SerialNo. 584,153

lf In the ignition systems of internal combustion enginesused inairplanes, motor vehicles and the like, high tension current passeswithin the distributor in the `forrnoi'asparlcbetween .a cen- Vtral;or:main terminal andaterminal for each cylinder in the engine. Theseterminals between which theVv sparks occur are enclosed in thedistributor by a cap which ts over the body thereof Iand, in the case 0fairplanes; both the body 'and the cap areoi metal. To'preventinterference jwith the radio with which such vehicles are I'equipped `itis necessary to'p'revent-the waves genjerated'by these sparks from`passing outside of the distributor. Furthermore,` it is not only essential thatentrance of water'b'etween-the cap and the lbody oftheldistributorbe prevented but la'lso air leakage from the interior of thedistributor, because 4the air` pressure within the distributor usedinplanesthat riseto high altitude must be maintained substantially higher,by supercharging than the* pressure of the circumambient air.' j It isa'relatively simplematterto prevent the electro-'magnetic waves generatedby the'sparks aforesaid from passing outside the distributor byproviding a substantially continuous metal contact between the cap andthe body of the distributor. It is also a rather simple matter toprovide 'a substantially air tight contact between the distributor capand body so that an air pressure which is substantially higher than thatof the circumambient air can be maintained within the body of thedistributor. However the problem of providing good electrical contactbetween the cap and the -body of the distributor, which involves the useof metal in some form or other, and, at the same time, forming an airtight contact between the cap and the body of the distributor issomewhat more dimcult of solution. A gasket which can be used to eiectsuch a combined radio shield and air seal must be adapted to bemanufactured rapidly at `comparatively low cost; must be yielding, andpreferably resilient to an appreciable degree to conform to 'and therebyform an air tight seal with the surfaces between which it is positioned;must be air impervious; and must provide a substantially continuousmetallic contact between the cap and body of the distributor.

It is the principal object of my invention to provide such a gasket andI accomplish this result by forming the gasket in the manner describedbelow and illustrated in the accompanying drawing in which:

Fig. 1 is a fragmentary elevation View to a greatlyenlarged' scale of mypreferred form' of gasket;

Fig. 2 isi afragmentary cross section ofmy preierred'iorni of gasket toastill greater'enlarged scale;

Figs; 3 and-'4 are fragmentary sections similar to 2 showing modifiedtypes of gaskets; and

Fig. 5 is a. fragmentary elevation viewtoan enlarged scale of one of theelements forming my preferred type ci gasket.

Referring to the drawings irepresents thecore of the gasket whichispreferably cylindrical and formed of rubber, or preferablwNeoprene orsome similar substance which isV resilient and deformable, so thatit canfunction as agasket, and yet moreresistant to the action ofl oils-andgreases than is rubber,

Wrapped around this core is a plurality' oflelectrical conductors havingclosely spacedportions thereof exposed'on the surface of the gasketl soasv to provide a substantially continuous electrical contactfbetw'eenthetwo metallic surfaces between Awhich the gasket is compressed. Theseconductors'are preferably braided together as shown at 6 in Fig. 1. Thepreferred form of conductor is shown in Fig. 5 and comprises a core 8 offibrous material such as thread or yarn around which is helicallywrapped a very thin gauge, fiat, metal ribbon 1. In Fig. 3, however, Ihave shown a wrapping formed entirely of metal conductors 2 which may bevery fine wires. It is to be understood that the conductors which arewrapped about the core are extremely tenuous and are not intended to,and do not, function as an armor or protection for the core, but only toprovide electrical conductivity between opposite sides of the gasketsubstantially throughout.

In Fig. 2, I have shown a gasket formed by wrapping .a plurality ofconductors 6, such as shown in Fig. 5, around a core l of rubber,neoprene or the like. Here, it will be apparent that the metal ribbonswhich are wrapped around the threads 8 are exposed on the surface o-fthe gasket.

In Fig. 4 I have shown a wrapping comprising wires 4 and threads ofyarns 5. As here shown, the Wires `and threads alternate, but it is tobe understood that groups of two or more wires and groups of two or morethreads may be braided together; the important thing being that closelyspaced portions of the wires, or other conductors employed, be exposedon the surface of the gasket to provide substantial continuity ofelectrical contact between two metallic surfaces in contact with saidgasket but on opposite sides thereof.

As thus formed, it will be apparent that none of the gaskets whencompressed will be absolutely air impervious because of the intersticeswhich exist between the conductors themselves, between the conductorsand the core and in the yarns or threads if such are employed.

Therefore, in order to make the gasket air impervious throughout Iimmerse it or run it through a dispersion or a solution of an airirnpervious material, such for example, as rubber or latex, in asuitable solvent so that all of the interstices in the gasket are filledthereby as shown at 3 in Figs. 2, 3 and 4. When the gasket is removedfrom the impregnating bath the solvent evaporates leaving theinterstices filled with air impervious material. The lm of rubber orother air impervious material used in impregnating which adheres to thesurfaces of the conductors which are exposed on the surface of thegasket may be removed by suitable wipers or,

preferably, by drawing the material through a die.

As pointed out above the drawings are to a greatly enlarged scale, andwhile the invention is not limited to any particular size of gasket itmay ybeunderstood that, in practice, the overall diameter would notordinarily exceed about lg.

What I claim is: l. A radio shielding and sealing gasket comprising acore of resilient material in the center thereof, a plurality ofmetallic conductors, cornprising thin, flat, metal ribbons helicallywrapped about' tenuous strands of yieldable material,

Aclosely braided around said core and having closely spaced, bareportions of said ribbons exposed substantially throughout the entiresurface of said gasket, and the interstices of said gasket beingsubstantially lled with a resilient, air-impervious substance preventingpassage of air transversely through said gasket; whereby, when 1 saidgasket is compressed between two surfaces spaced thereby, said surfaceswill be in substan- .tially continuous electrical contact through saidvgasket and the space between said surfaces will be effectively sealedagainst the passage of air and moisture in the zone of said gasket.

' 2. A radio shielding and sealing gasket comprising a core of resilientmaterial, a plurality of electrical conductors, comprising tenuousstrands of brous material having thin, at, metal ribbons helicallywrapped about them., braided closely together around said firstmentioned core with closely spaced, bare portions of said ribbonsexposed on the surface of said gasket, and the interstices in saidgasket bein-g substantially lled with a yielding, air-imperviousmaterial preventing passage of air transversely through said gasket;whereby, when said gasket is compressed between two surfaces spacedthereby said surfaces will be in substantially continuous electricalcontact through said gasket and the space between said surfaces will beeffectively sealed against the passage of air and moisture in the zoneof said gasket.

.ADRIAN A. PIERSON, J R.

REFERENCES CITED The following references are of record in the le ofthis patent:

Y UMTED STATES PA'I'ENTS Number 115,567 `Australia, July 16, 1942

